Preparations consisting of aqueous solutions of polyethyleneglycol and electrolytes, such as, anhydrous sodium sulfate, sodium bicarbonate, sodium chloride and potassium chloride are known for use in the rapid washing of the colon for diagnostic purposes. When a powerful gastrointestinal wash is required, this preparation is generally administered orally in a quantity of about four liters, the composition per liter being typically the following: polyethyleneglycol 59 g, sodium sulphate 5.68 g, sodium bicarbonate 1.68 g, sodium chloride 1.46 g, potassium chloride 0.745 g and water to make up to 1 liter.
The advantages of using such preparations are a drastic reduction in the wash time (from 2-3 days to 4-5 hours) and the minimization of water and electrolyte losses.
These represent substantial improvements which derive from two essential characteristics of the preparation, namely its isoosmoticity with the physiological liquids, and the balance of the ionic species in solution, so as to compensate the transport mechanisms which regulate gastrointestinal absorption.
These characteristics result in substantial isotonicity between the preparation and the intra and extracellular fluids at the tissues of the digestive tube walls.
In developing such preparations, this isotonicity was obtained by experimentally balancing the ionic species in solution, and also by calculating the osmotic pressure and evaluating the mechanisms which control transfer at the gastrointestinal walls.
A serious drawback of these known preparations is, however, their decidedly unpleasant bitter, saline taste, which in the more sensitive patients can lead to vomiting, thereby preventing ingestion. However, the requirement of solution isotonicity, which as stated is necessary to obtain the aforesaid advantages, does not generally allow, or at least makes very problematic, the introduction of water-soluble adjuvants into known formulations as they would alter this isotonicity. In this respect, some commercial preparations expressly state that taste correctors must not be added on diluting the preparation.
Furthermore, in the aforesaid preparations of the known art it is not opportune to add appreciable quantities of substances which can be fermented by the intestinal flora, because gas could form which could be extremely dangerous in cases of colonoscopy with electrocautery. Neither is it possible to introduce water-soluble substances in quantities such as to alter the osmotic conditions of the solution. The effect would be to lose the effectiveness and tolerance of the preparation. Neither is it possible to introduce electrolytes which would significantly alter the concentration of one or more ionic species present in the preparation. The result would be similar to that produced by altering the osmolarity. A further impediment to adding water-soluble substances for taste correction, in particular edulcorators, is that even the most common natural sweeteners such as saccharose, fructose, glucose and sorbitol would cause fermentation of the preparation and a change in its osmolarity.
For other edulcorators such as synthetic sweeteners there is a further problem in addition to the aforesaid general problems, namely the problem of toxicity at high doses, so that the acceptable daily dose (ADD) must be taken into account. Remembering that the preparation of the known art is taken orally in a quantity of four liters of solution per unit of administration, practically all known synthetic edulcorators would have to be administered in effective doses which are incompatible with the ADD fixed by regulations.
According to the present invention it has now been found possible to provide a preparation for oral use of the aforesaid kind which while being unaltered in terms of its capacity for rapid gastrointestinal washing is of substantially changed taste in the sense of being in fact pleasant for the patient.
According to a further aspect of the present invention, it has also been found that this preparation not only performs an effective gastrointestinal wash but at smaller doses demonstrates effective activity as a cathartic laxative.
The invention, which produces the aforesaid surprising effects and other advantages which will be apparent hereinafter, comprises an orally administered pharmaceutical composition for use in gastrointestinal washes, particularly for diagnostic use, or as a cathartic laxative of the type containing polyethyleneglycol, anhydrous sodium sulphate, sodium bicarbonate, sodium chloride and potassium chloride, characterised by also containing the following components: saccharin, acesulfame-K and a flavoring chosen from the following: mandarin, fresh fruit flavourings. According to a further embodiment, the composition of the present invention also contains sodium cyclamate.
According to the invention, the addition of said components in the suitable concentration ranges hereinafter defined has been found not to alter the isotonicity of the final solution, as is necessary for correct and satisfactory gastrointestinal washing within the short time required, i.e. a few hours. It has also been found not to induce the other feared effects, i.e. fermentation and ionic unbalance, and is able to maintain the composition ADD within acceptable values. These effects are combined with a pleasant taste such as to obviate all problems of its administration to the patient.